The market for positioning sensors, presence and proximity functions in mobile and wearable devices is significantly growing. For example, today a lot of smart phones include multiple positioning technologies such as GPS and Wi-Fi which provide a more or less accurate geographic position of the devices, for example latitude, longitude and altitude. This position information may be used by a plurality of applications including for example applications for monitoring and supporting sports activities and social networking applications.
These positioning technologies are rapidly improving in position accuracy, speed and power consumption. Furthermore, use cases are extending and a significant use case domain to be addressed may be the peer-2-peer positioning. This allows a determination of the relative position between two or more devices, which opens new device functionalities and new user behaviour.
Technologies for determining a distance and a direction from one device to another device include for example a line time measurement (FTM) and a measurement of angle of arrival/departure (AoA/AoD). The fine time measurement is used to determine the distance between two devices by measuring the time it takes for radio waves to propagate between the two devices. The angle of arrival/departure measurement is used to determine a direction for one device towards another device Usually, multiple antennas are used (synthetic antenna arrays are also usable) and the direction is derived from a comparison between the times when a transmitted signal arrives at each antenna. Variations of these two technologies are implemented in standards like WLAN, BLUETOOTH® and 3GPP machine type communication (MTC).
The accuracy of these technologies highly depends on the characteristics of the environment, for example the amount of multipath propagation, and the radio frequency characteristics of a wireless protocol, for example a modulation type and a bandwidth. However, the bandwidth may be very limited, for example in WLAN/Wi-Fi as a baseline uses 20 MHz channels, where each network is always set on one specific channel.
Therefore, there is a need in the art for methods and devices which address at least some of the above short comings in fine time measurements and angle of arrival/ departure measurements. There is in particular a need in the art to improve the accuracy of these measurements within the limits of the standardized protocols, for example, WLAN, BlUETOOTH® and 3GPP.